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Allow setting of more DNS options via API; from Nick Mathewson!!!

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svn:r318
This commit is contained in:
Niels Provos 2007-01-27 04:27:59 +00:00
parent b776b2da72
commit 78f2aa300c
2 changed files with 65 additions and 25 deletions
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88
evdns.c
View File

@ -1898,6 +1898,64 @@ strtoint(const char *const str) {
return r;
}
// helper version of atoi that returns -1 on error and clips to bounds.
static int
strtoint_clipped(const char *const str, int min, int max)
{
int r = strtoint(str);
if (r == -1)
return r;
else if (r<min)
return min;
else if (r>max)
return max;
else
return r;
}
// exported function
int
evdns_set_option(const char *option, const char *val, int flags)
{
if (!strncmp(option, "ndots:", 6)) {
const int ndots = strtoint(val);
if (ndots == -1) return -1;
if (!(flags & DNS_OPTION_SEARCH)) return 0;
log(EVDNS_LOG_DEBUG, "Setting ndots to %d", ndots);
if (!global_search_state) global_search_state = search_state_new();
if (!global_search_state) return -1;
global_search_state->ndots = ndots;
} else if (!strncmp(option, "timeout:", 8)) {
const int timeout = strtoint(val);
if (timeout == -1) return -1;
if (!(flags & DNS_OPTION_MISC)) return 0;
log(EVDNS_LOG_DEBUG, "Setting timeout to %d", timeout);
global_timeout.tv_sec = timeout;
} else if (!strncmp(option, "max-timeouts:", 12)) {
const int maxtimeout = strtoint_clipped(val, 1, 255);
if (maxtimeout == -1) return -1;
if (!(flags & DNS_OPTION_MISC)) return 0;
log(EVDNS_LOG_DEBUG, "Setting maximum allowed timeouts to %d",
maxtimeout);
global_max_nameserver_timeout = maxtimeout;
} else if (!strncmp(option, "max-inflight:", 13)) {
const int maxinflight = strtoint_clipped(val, 1, 65000);
if (maxinflight == -1) return -1;
if (!(flags & DNS_OPTION_MISC)) return 0;
log(EVDNS_LOG_DEBUG, "Setting maximum inflight requests to %d",
maxinflight);
global_max_requests_inflight = maxinflight;
} else if (!strncmp(option, "attempts:", 9)) {
int retries = strtoint(val);
if (retries == -1) return -1;
if (retries > 255) retries = 255;
if (!(flags & DNS_OPTION_MISC)) return 0;
log(EVDNS_LOG_DEBUG, "Setting retries to %d", retries);
global_max_retransmits = retries;
}
return 0;
}
static void
resolv_conf_parse_line(char *const start, int flags) {
char *strtok_state;
@ -1907,7 +1965,7 @@ resolv_conf_parse_line(char *const start, int flags) {
char *const first_token = strtok_r(start, delims, &strtok_state);
if (!first_token) return;
if (!strcmp(first_token, "nameserver")) {
if (!strcmp(first_token, "nameserver") && (flags & DNS_OPTION_NAMESERVERS)) {
const char *const nameserver = NEXT_TOKEN;
struct in_addr ina;
@ -1931,30 +1989,9 @@ resolv_conf_parse_line(char *const start, int flags) {
search_reverse();
} else if (!strcmp(first_token, "options")) {
const char *option;
while ((option = NEXT_TOKEN)) {
if (!strncmp(option, "ndots:", 6)) {
const int ndots = strtoint(&option[6]);
if (ndots == -1) continue;
if (!(flags & DNS_OPTION_SEARCH)) continue;
log(EVDNS_LOG_DEBUG, "Setting ndots to %d", ndots);
if (!global_search_state) global_search_state = search_state_new();
if (!global_search_state) return;
global_search_state->ndots = ndots;
} else if (!strncmp(option, "timeout:", 8)) {
const int timeout = strtoint(&option[8]);
if (timeout == -1) continue;
if (!(flags & DNS_OPTION_MISC)) continue;
log(EVDNS_LOG_DEBUG, "Setting timeout to %d", timeout);
global_timeout.tv_sec = timeout;
} else if (!strncmp(option, "attempts:", 9)) {
int retries = strtoint(&option[9]);
if (retries == -1) continue;
if (retries > 255) retries = 255;
if (!(flags & DNS_OPTION_MISC)) continue;
log(EVDNS_LOG_DEBUG, "Setting retries to %d", retries);
global_max_retransmits = retries;
}
const char *val = strchr(option, ':');
evdns_set_option(option, val ? val+1 : "", flags);
}
}
#undef NEXT_TOKEN
@ -1987,7 +2024,7 @@ evdns_resolv_conf_parse(int flags, const char *const filename) {
if (fstat(fd, &st)) { err = 2; goto out1; }
if (!st.st_size) {
evdns_resolv_set_defaults(flags);
err = 0;
err = (flags & DNS_OPTION_NAMESERVERS) ? 6 : 0;
goto out1;
}
if (st.st_size > 65535) { err = 3; goto out1; } // no resolv.conf should be any bigger
@ -2016,6 +2053,7 @@ evdns_resolv_conf_parse(int flags, const char *const filename) {
if (!server_head && (flags & DNS_OPTION_NAMESERVERS)) {
// no nameservers were configured.
evdns_nameserver_ip_add("127.0.0.1");
err = 6;
}
if (flags & DNS_OPTION_SEARCH && (!global_search_state || global_search_state->num_domains == 0)) {
search_set_from_hostname();

2
evdns.h
View File

@ -213,6 +213,7 @@
* 3 file too large
* 4 out of memory
* 5 short read from file
* 6 no nameservers in file
*
* Internals:
*
@ -298,6 +299,7 @@ struct in_addr;
struct in6_addr;
int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
int evdns_set_option(const char *option, const char *val, int flags);
int evdns_resolv_conf_parse(int flags, const char *);
#ifdef MS_WINDOWS
int evdns_config_windows_nameservers(void);